Compound for and method of treating metals



Patented Feb. 26, 19 24.

MATTHEW GREEN, OF DETROIT, MICHIGAN, ASSIGNO'R TO' PARKER RUST-PROOF COM- PANY, OF DETROIT. MICHIGAN, A. CORPORATION OF MICHIGAN.

COMPOUND FOR AND METHOD OF TREATING METALS.

Ho Drawing.

and Methods of Treating Metals, of which the following is a specification.

My invention relates to a composition for removing or freeing the surface of iron, steel or alloys of the same from rust and at the same time so treating the metal as to pre-' vent or retard further oxidation or rusting. My invention also relates to the method of applying or using my compound successfully.

It is-one of the objects of my invention to provide such a compound which will quickly and thoroughly remove rust from metals and which is composedof relatively inexpensive ingredients. i

It is a well known fact that phosphoric acid in vTirious forms and solutions has been found to be an excellent rust proofing agent. The salts formed upon metals by the action of phosphoric acid when applied to the metal are of a permanent nature so that the metal is not affected by atmospheric conditions, in so far as oxidationor rust is concerned.

It has not been found practicable, however, to use phosphoric acid alone for removing rust formed upon metals for the reason that its action upon the rust is so slow as to make its use impracticable.

It is one of the objects-0f my invention, therefore, to add to a solution of phosphoric acid a quantity of some reducing agent sufficient to hasten the action of the solution upon the rust. agent is to' absorb theoxygen of which the rust is largely com osed in such a manner that the rust is easi y and quickl removed.

As a specific reducing agent, I ave found that sodium hypophosphite used in conjunction with phosphoric acid' and water will perform very successfully the desired results. While I do .not wish to be limited to any specific amounts of the ingredients used in my composition, I have found that the folmetals.

The purpose of the r'educlng Application filed September 28, 1921. Serial No. 503,933.

lowing formula will give very desirable results:

Parts (weight). 50% Phosphoric acid 75 Water 20 Sodium hypophosphite 5 The amount of sodium hypophosphite used may be varied accordingly to the depth of the rust on the metal. That is to say, if there is a comparatively thin coating of rust, a relatively small amount of sodium by 0- phosphite may be used, whereas if a re avtively thick coating of rust is encountered it will probably be found desirable to use a phite.

The solution may be applied to the metal v cold and by means of either a brush or by,

dipping the metal into a bath of the solution. It may be found necessary when metal is heavily coated withrust and the solution is applied with a brush to give more than one coating of the solution to the metal. When the metal is placed in a bath it should be allowed to remain therein until cleaned, the time depending upon the condition of the The action of my solution will .tend to reo that a slight scum or dirt will remain on the metal after beingtreated with my solution and it is often desirable that this be removed. In order to remove this, the metal may be rinsed either in hot water or in a hat solution of say 5% normalso'dium phosate. fer to wash or rinse it with hot water. If, however, they metal is not to be painted,.I prefer to wash or rinse it in the solution of sodium phosphate as this will add to the rust resisting qualities of the surface of the metal. The presence ofphoshoric acid 1n the solution with which the metal is. first treated gives the initial rust resisting qual- If the metal is to be painted, I pre-- ities, so as'to ordinarily resist or retard the formation 01 further deposits of rust after the metal is so treated.

While I have found it desirable to use phosphoric acid together with a reducing agent in removing the rust, I do not wish to be limited to that ingredient as other ingredients which will act in conjunction with the reducing agent and cause it to work up on the rust may be equally as Successful as far as the rust removing properties of my solution are concerned.

It will thus be seen that my invention performs a two fold purpose, namely, the quick and thorough removal of rust from metals, and the prevention of further formation of rust on the metal.

Itis obvious that some changes may be made in the quantities of the various ingredients of my solution, in the ingredients used as a reducing agent (it being practicable to use any form of reducing agent) and in the method herein described for utilizing the same without departing from the spirit of the invention therein, and I do not wish to limit myself to the exact proportions or exact methods herein described, it being my intention to cover by my claims such changes as may be reasonably included within the scope thereof.

What I claim is: v

1. A compound for treating metals embodying phosphoric acid and a reducing agent, said phosphoric acid being present in a relatively large amount, suflicient to act inconjunction with the reducing agent to remove rust and to at the same time rust "proof the metal.

2. A .compound for treating metals embodying phosphoric acid and sodium hypophosphites, the phosphoric acid being present in a relatively large amount, sufiicient to act in conjunction with the sodium hypophosphite to remove rust and at the same time rust proof the metal.

3. A compound for treating metals embodying )hosphoric acid, sodium hypophosphite and water, the phosphoric acid being present in a relatively large amount, sufiicient to act in conjunction with the sodium vhypophosphite to removerust and at the the sodium hypophosphite to IQIIIOXTG rust.

and at the same time rust proof the metal and then rinsing the metal with a solutio of sodium phosphate.

6. The method of treating metals which consists in subjecting the metal to 'a solution embracing phosphoric acid and a reducing agent, wherein the phosphoric acid is present in a relatively large amount sufficient to act in conjunction with the reducing agent to remove rust and at the same time rust proof the metal, and then rinsing the metal.

MATTHEW GREEN. 

